Embodiments of this invention relate generally to printed circuit boards and components coupled thereto and in particular, to an electronic assembly with solderable heat sinks and methods of manufacture.
Processors and related computer components are becoming more powerful with increasing capabilities, resulting in increasing amounts of heat dissipated from these components. Similarly, package and die sizes of the components are decreasing or remaining the same, which increases the amount of heat energy given off by the component for a given unit of surface area. Furthermore, as computer-related equipment becomes more powerful, more chips are surface-mounted to the printed circuit board, and more and more components are being placed inside the equipment or chassis which is also decreasing in size, resulting in additional heat generation in a smaller volume of space. Increased temperatures can potentially damage the components of the equipment, or reduce the lifetime of the individual components and equipment. In addition, some components are more susceptible to damage resulting from stress and strain occurring during testing, packaging, and use.
Heat sinks have been used to assist in dissipating heat from the processor and other heat-producing components within a housing. However, the overall size of the heat sink is limited by the volume constraints of the housing, and the footprint and/or the size constraints. Heat dissipation has been increased by using fasteners such as mechanical clips, epoxy, glue, and/or rivets which physically hold a heat sink to the processor package mounted on a printed circuit board. For some heat sinks, spring-loaded fasteners are used to couple the heat sink with the heat-producing components to enhance heat dissipation from the heat-producing components. However, such fasteners require one or more additional final assembly process steps, which results in requiring additional manufacturing resources after all of the soldering steps are completed. These additional manufacturing steps increase the cost of providing a thermal solution to heat-producing components such as chipsets.
FIGS. 1, 2, 3, and 4 illustrate conventional manners 100, 200, 300, and 400, respectively, of coupling the heat sink to heat-producing components such as chipsets and/or microprocessors. FIG. 1 illustrates using a mechanical clip 110 to couple heat sink 120 to heat-producing component 130 mounted on a printed circuit board 140 to enhance heat dissipation from the heat-producing component 130. FIG. 2 illustrates using epoxy and/or glue 210 to couple heat sink 120 to heat-producing component 130. FIG. 3 illustrates using spring-loaded fastener 310 to couple heat sink 120 to heat-producing component 130. FIG. 4 illustrates using rivets 410 to couple heat sink 120 to heat-producing component 130. All of these prior art techniques require one or more additional final assembly process steps, which increases the cost of providing a thermal solution to heat-producing components. In addition, the prior art techniques illustrated in FIGS. 1, 3, and, 4 require substantial circuit board space to mechanically retain the heat sink in place.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a low-cost technique that consumes substantially less circuit board space than the prior art techniques to provide a low-cost thermal solution to the heat-producing components.